Traditional integrated circuit (IC) comprises of a micro-controller, input/output ports and additional functional specific circuits designed to perform special functions. Other application specific functional circuits such as resistor identification circuits are provided outside the integrated circuit making use of discrete digital, analog components, or additional special function IC such as operational amplifiers and comparators. Since application circuit requirements vary, manufacturers are required to provide a family of micro-controllers IC each having a different functional, performance, or interfacing specifications to meet the different application needs of the users. Applicant's prior art disclosure, a toy designed by the applicant for Mattel Toys named ARCO—Once Upon A Time Playset during April 1994, discloses a simple low cost resistor sensing circuit which trigger a voice generating microcontroller chip to produce different voice response in according to the contact of four different resistor values.